All this concentration about CO2 emissions, rather than 'de-stabilising the climate', people forget that CO2 is broken down by vegetation and thus contributes to the ecology (grow more vegetation and more CO2 will be absorbed) whereas if you compare the CO emisions of diesel and petrol cars there is a vast difference because diesel engines only emit tiny amounts of CO compared to petrol engines. It's commonly know that if you run a petrol engine in (say) a garage with the door closed, you will die of CO poisoning, but do the same with a diesel engine and you might get a headache, but that's all.
On the issue of particulates, these are emitted by both diesel and petrol cars with diesel cars producing them at the same (low) level throughout the life of the car due to the 'particulate trap' fitted to the exhaust, however with petrol engines, the amount starts off low with a new cars and steadily increases over the life of the car ending up far exceeding the amount emitted by diesel engines.
By the way, the sooty deposits in the tailpipe of petrol cars are due to the unleaded petrol being used nowadays; leaded petrol, although more harmful in the long run, was 'cleaner' in terms of soot deposits. The same goes for spark plugs; once upon a time a sooty spark plug indicated the mixture was too rich whereas a 'normal' mixture was a brownish deposit on the electrodes or even clean electrodes; nowadays the 'norm' is to have sooty spark plugs.